癌相关间充质干细胞在癌组织不断增生和重塑中的作用机制研究

Cancer is a kind of unstable organization continuously undergoing growth and tissue remodeling. In the normal adult, mesenchymal stem cells (MSCs) are key cells for organizational structure and wound-healing. Notwithstanding there are evidences to demonstrate that MSCs abnormally accumulated in cancer tissues play important role in tumor cells growth, metastasis and tumor immune, and the role of cancer-associated MSCs in the continuous tumor tissues growth and remodeling process has yet to be studied. Studies have shown that cancer-associated fibroblasts tamed by tumor microenvironment changed their biological function and characteristic obviously, while, the change of the biological function and characteristic of cancer-associated MSCs which enriched in cancer tissues still need further research. In view of the important physiological functions of MSCs to normal organizations and the important role of cancer-associated MSCs in tumor, this project was designed to reveal the biological characteristic and function changes of cancer-associated MSCs in tumor microenvironment, and to clarify its tumor chemotactic properties and the possible incentives. And we will also use animal experiments, from the point of view of the organization development, to reveal the action mechanism of cancer-associated MSCs in the continuous cancer tissue regeneration and remodeling process。This project will also been used to explore the possible role of MSCs in the tumor microenvironment, which they played in cancer cells growth and metastasis.

癌组织是一类不断生长和重塑的不稳定组织。在正常成体，间充质干细胞（MSCs）是组织结构构建、损伤修复的重要细胞。虽有证据表明癌组织内异常富集的MSCs对肿瘤细胞生长、转移、肿瘤免疫均有重要影响，然而癌相关MSCs在肿瘤组织不断生长和重塑过程中发挥何种作用尚有待研究。研究显示癌相关成纤维细胞受肿瘤微环境驯化其功能、性状改变明显，而富集于癌组织内的癌相关MSCs性状功能的变化还需研究探明。鉴于MSCs的重要生理功能和癌相关MSCs对肿瘤的重要作用，本项目旨在研究肿瘤微环境内癌相关MSCs生物性状和功能的变化，阐明其对肿瘤的趋化特性和可能的诱因；并用动物实验，从组织发育学的角度揭示其对癌组织不断新生构建和重塑的作用机制，探讨其在肿瘤微环境中所发挥的作用，及其与癌细胞生长、转移的关系。

癌是一种实体组织，癌细胞是其中的主要细胞成份，而间充质细胞也在癌的组织构成、肿瘤生物性状中发挥重要的作用。研究显示癌组织中存在大量的间充质干细胞，而这些间充质干细胞的生物性状、在癌组织中发挥什么样的作用尚有待研究。我们以结直肠癌作为组织来源研究其中的癌来源间充质干细胞（CA-MSC），并用脂肪组织来源的脂肪干细胞(A-MSC)作为参照。对两类细胞诱导分化，均可诱导分化为成脂、成骨、成软骨细胞。两类细胞也可分化成平滑肌细胞、神经相关细胞，并且CA-MSC更易于诱导分化为神经相关细胞。对两类细胞的全蛋白质谱检测，以质谱低检测效能情况下，仍均能发现两类细胞表达神经相关的蛋白成份，且均表达nestin。这则提示CA-MSC与A-MSC具有神经干细胞样的属性。进行标志物的流式检测，则进一步明确了两类细胞均表达神经干细胞的标志物nesting、mushashi-1，且两类细胞均未表现出典型的间充质干细胞的检测结果。Western blot亦肯定了nestin、mushashi-1及其他干细胞标志物的表达情况。为此我们按神经干细胞培养方案培养MSC，两类细胞均能出现成球状生长。成球生长的细胞wimintin\ nestin均呈阳性，则表明来源于MSC成球生长的细胞呈现类神经干细胞样性状。对两类配对细胞的转录组二代测序检测同样显示MSC存在神经相关物质的RNA水平的表达，并且MSC均表现出WNT5A/5B的高表达特征。WNT家族与细胞的干性相关，可能WNT高表达有助于肿瘤干细胞与自身干细胞属性的维持。MSC中明显存在类似于神经干细胞的亚群。这类干细胞亚群的培养与应用将会有巨大的医学与生物学意义，有利于开发新的干细胞体系。MSC与癌细胞的共生性特征，不同文献有不同的结果。在体外RTCA检测中，两类MSC与结直肠癌细胞株SW480/SW620也呈现出抑制与共生的矛盾结果。为此我们进行MSC与癌细胞的共移植实验与体内趋化实验。已有的结果提示MSC并不能在以血管入注中协助SW620、SW480的转移与成瘤，癌细胞以这种方式入体，均出现消失。余动物实验的结果尚待进一步研究。